[CommanderRachek]

I know this isn't exactly answering your question, but have you considered doing something non-robotics related? You might have fun taking a photography course or something. Just a thought.

If you want to do something productive, consider learning some linear algebra. Knowing how to do matrix row operations and compute eigenvalues will be very useful when you get to college. Knowing basic vector operations is a good skill set, as well. Be careful with self-study courses, however: I did a linear algebra self-study my senior year and had a terrible time getting myself to do work instead of just putter around the shop.

You can never have enough practice with any kind of CAD software. I had a lot of fun drawing my trombone in Inventor. You could pick something really intricate to draw that will take you a long time.

If you're all CADed out, you could also start learning how to use MatLab (I think you can get a one-year license for ~$30). It's an immensely powerful tool, and if you'll be majoring in engineering or any of the hard sciences I can guarantee you'll use it in college. It's also a good skill to put on a resume; an engineering intern who can use MatLab effectively is orders of magnitude more useful than one who can't. (If you'll be majoring in math, like me, you could also start learning how to use Mathematica and/or Maple.) If you don't already know some, knowing how to do at least a little C programming is also a good skill to have.

If your school has any advanced chemistry courses, you could take one of those. I took IBH Chemistry junior and senior year and had a blast. It was no small amount of work, but I learned a lot. I got a lot of interesting problem solving practice, and I learned a surprising amount of stuff that was directly applicable to FRC.